Blackstar HT-20R

[EL34]

I have worked on 1000's of vintage hand wired Valve amps over the years. I never wanted to work on PCB amps or solid state amps. I always sent PCB and solid state amps to another shop  because I had so much vintage amp work and because I hate working on PCB amps. :(

I broke down and helped friends of mine today.
They called me and asked if I could take a look at his 6 month old Blackstar HT020R.

Friends of mine have a 16 year old son who is learning to play. No sound at all coming out of his Blackstar HT-20R amp. All lights were on, switching worked and the valves were fine.
 The components are so tiny in this amp, it's insane.  No solder joints broken that I could see on front panel or the speaker jacks or on the board, but even with magnification, this amp was a tiny parts nightmare inside.

 Thanks to a Youtube video I was able to quickly spot the same inductor as being bad. There was a smoky film next to L1 on the board surface and there was a tiny solder blob stuck to the inductor. The inductor just fell off the board when I poked it with a chopstick. I jumpered across the two half's of the inductor and the amp came back to life.

The dealer that sold the amp new had a heart attack and will not be back open for several weeks. They can see what he can do for them when he returns.
For now, the boy has an amp and is able to play and so that is a happy ending.

The video that saved the amp is here
He posted a picture of the input jack schematic and that's when I went back to the amp to have a look after seeing nothing with magnification

And here is the input jack schematic he posted in the Youtube video. Look at the tiny smd inductor L1 and the jumpers I installed to get the boy back  to playing his guitar.

[EL34]

Here's a shot of the released smoke next to the inductor
I am not sure how you can blow up an inductor that is connected to the input jack, but there you have it.

Unfortunately it was so tight in there that my solering iron touched that plastic capacitor body and melted it. It was fine, no real damage

[EL34]

I would have never spotted that inductor problem without seeing that Youtube video 

[shooter]

looks like some engineer didn't spec for hot pickups or pedal amplification

When all the circuit boards started moving to surface mount I told my boss "It's over"   
I priced out a work station, he pooped bricks 


we did a few small "fixes" by wrapping 26ga solid copper around your pencil tip, hammer out the end of the wire to get a good fit on the solder connections.  Still needed 10X eyes to read the parts!


we are officially a throw-away-world

[PRR]

I think his guitar cord shell touched some other "ground". Maybe there is a ground fault at his house. Maybe a buddy has a miswired 1960s amplifier. Maybe he has one of those ungrounded laptops with two capacitors across the line and 60V on the chassis.

I hope you showed him the difference SMD and turret-wire. That one may live decades and go to auction at high prices; the other is dead in 6 months unless you know a really smart fixer.

That's a $700 amp!! It quits in 6 months, you paid $115+/month for the dubious pleasure.

[glass54]

Well done EL34. You could have fitted a pair of small ferrite beads onto those 2 links and the repair would have been completed and to a high standard.
My favourite part of the video was at 5min 14secs when the wooden mallet came out. 
But it wasn't used the way I thought!
Over a decade ago, Laney (maybe VC15??) did a Hybrid Tube/SMD amp which was obviously better than the Blackstar but still had reliability issues. It was a nightmare to pull apart with multiple PCBs, but relatively easy to repair.
Thanks for sharing (and dare I say simplicity in construction is beautiful)
Kind regards
Mirek

[EL34]

The Blackstar is basically a throw away amp because of that smd board
That inductor that blew up was maybe only 2mm long


Or if it fails completely, gut it and install a hand wired board

[uki]

@EL34 , SMD is indeed a nightmare, it is a common thing now days, cellphone technicians to use a microscope to see the components.

we are officially a throw-away-world

It is been for decades

I hope you showed him the difference SMD and turret-wire. That one may live decades and go to auction at high prices; the other is dead in 6 months unless you know a really smart fixer.

I would have!

[rake]

This would be a great candidate for a guy and replace!
Maybe a 6V6 Plexi with an added gain stage and an effects loop.
Then this young man would have an amp that could
rattle the bedroom windows with some superb tone!